1. Field of the Invention
The present invention relates to an improved lumbar support device for use in a vehicle seat which is so constructed as to be able to control the supporting pressure of the lumbar support section of the seat by moving a pair of lumbar plates in a longitudinal direction by means of operation of an operation member.
2. Description of the Prior Art
Conventionally, lumbar support devices having a plurality of lumbar plates are generally constructed such that two lumbar plates respectively provided right and left of an operation shaft mounted within the lumbar support section of a seat are moved longitudinally at the same time by rotating the operation shaft. Therefore, although the conventional lumbar support devices of such construction can support the entire lumbar support section of the seat with uniform pressure, they are not be able to control their supporting pressure partially, for example, they can not support only the upper portion of the lumbar support section with higher pressure and the upper portion of the lumbar support section with lower pressure at the same time. As a result of this, the above-mentioned prior art devices can not provide a comfortable sitting touch.